Swivel electrical connecter



Sept. 29, 1936. CALDWELL 2,055,999

SWIVEL ELECTRICAL CONNECTER Filed July 6, 1932 2 Sheets-Sheet 1 Sept. 29, 1936. 15 A DW 2,055,999

SWIVEL ELECTRICAL CONNECTER Filed July 6, 1952 2 Sheets-Sheet 2 Ill Patented Sept. 29, 1936 PATENT OFFICE 2,055,999 SWIVEL ELECTRICAL CONNECTER Albert Earl Caldwell, Galesburg, 11].. assignor of one-half to George D. Ladd, Oak Park, Ill.

Application July 6, 1932, Serial No, 621,079

6Claims. (or. 173-324) The primary object of the present invention is to produce a simple and novel quickly detachable electrical connection which will permit one member thereof to turn freely with respect to the other. 9

A further object of the present invention is to produce an electrical connecting device of the quickly detachable type which will cause the receptacle or a portion thereof to turn automatical- 1y when contact fingers are pressed against the same, so as to bring the finger-receiving openings into registration with the fingers and permit the fingers to enter the openings; thereby making it unnecessary for the plug or other element that carries the contact fingers to be turned in order to enter the fingers in the openings therefor in the receptacle.

The various features of novelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawings,

5 wherein:

Figure 1 is an elevation of what may be termed an intermediate receptacle and a plug on the end of a cable or cord provided with contact fingers adapted to enter the receptacle; Fig. 2 is a central longitudinal section, on a larger scale, through the receptacle shown in Fig. 1; Fig. 3 is a section on line 3-3 of Fig. 2; Fig. 4 is a top plan view, on a smaller scale than Figs. 2 and 3, of the rotacable cover for the receptacle; Fig. 5 is a section on line 5-5 of Fig. 4; Fig. 6 is a section on line 6-6 of Fig. 2; Fig. 7 is a bottom plan view of-the central portion of the receptacle; and Fig. 8 is a view similar to Fig. 2, showing a modification.

In the drawings I have shown the invention as applied to an intermediate receptacle which itself is adapted to be plugged into a wall receptacle, but it will, of course, be understood that the invention is not limited to a receptacle adapted for this particular use but may be employed in connection with wall receptacles, branch plugs, and the like, as well as in intermediate receptacles.

Referring to Figs. 1-7 of the drawings, I represents a cylindrical cup-shaped member or receptacle, over the open end of which is placed a disk-like cover 2, both of these members being formed of insulating material. Extending through and fixed to the bottom of the recep- 5 tacle, at the center of the latter, is a metal post 3.

The bottom wall of the receptacle is provided with a sleeve-like part or hub 4 projecting upwardly therefrom around the post. The post serves as or is connected to a terminal for. one side of an electric circuit. When the device is used as an 6 intermediate receptacle, the post is connected to the receptacle. In the arrangement shown, the

contact finger 5 is L-shaped, one arm thereof ly- 10 ing in a recess or depression II in the bottom face of the receptacle and having an opening through which the post passes. The post is enlarged in diameter immediately above the sleeve or hub 4 so as to provide a shoulder resting on 15 the upper end of this sleeve or hub. The lower end of the post is riveted over, as indicated at I, therebyvdrawing the transverse arm of the contact element 5 against the receptacleand the enlarged part of the post against the upper end 20 of the sleeve or hub. The contact finger 6 extends through the bottom wall of the receptacle and, at its upper or inner end, has a transverse arm 8 seated in a suitable recess or pocket in the upper face of the bottom wall of the receptacle 25 and provided with an opening through which the sleeve or hub extends and in which it fits. The member 8 is provided with an upwardly-projecting frusto-c'onical part 9 that surrounds the sleeve or hub. 30 The cover member of the receptacle is provided with a long tubular stem l0 extending downwardly from the same around the post. The internal bore of the tubular stem is much greater in diameter than the diameter of the post. Sections 35 of the tubular wall of the stem, diametrically opposed to each other, and extending from top to bottom, are cut away; so that the stem in effect consists of two trough-like legs having their concave sides directed toward each other, but spaced 4 apart from each other. The bore of the stem member is preferably non-circular being, in the arrangement shown, hexagonal. On the stem are mounted'contact pieces adapted to be engaged by two contact fingers on a plug or the like, which 5 contact fingers are adapted to enter the receptacle through suitable openings l2 and I3 in the cover. The openings l2 and I3 lie above and just outwardly from what maybe termed the slots or passages l4 and I5 between corresponding edges 50 of the two legs of the stem. Therefore, in order properly to engage with contact fingers inserted in the receptacle, the contacts in the receptacle should lie just below the openings 12 and I3 or, stated in another way, just opposite the slots or Open spaces I4 and I5 in the stem. In the arrangement shown, each of the contact pieces in the receptacle is L-shaped. Thus, one of the contacts consists of an arm I6 lying beside the stem, opposite the slot I5 in the stem, together with a second arm I 1 arranged at right angles to the arm I6 and extending transversely across the stem. The second contact piece consists of an arm I8, similar to the arm I6, but lying just outside of the slot I4 in the stem; the arm I8 being provided at its upper end with a cross arm I9 which extends tranversely across the stem. As a matter of fact, the two contact pieces may be exactly alike excepting that the arm IS in one of the pieces must be provided with a hole large enough to permit the post to extend through the arm without coming in contact therewith; this hole being illustrated at 20. The arms I1 and I9 are so shaped that hexagonal portions thereof fit the hexagonal bore of the stem while what may be termed neck portions thereof extend from the hexagonal portions to the arms I6 and I8, respectively, through the slots I4 and I5 in which they slidably fit. It will, therefore, be seen that the contact pieces may be assembled on the stem by inserting their cross-arms into the open end of the bore of the stem and pushing them up along the stem until the under side of the cover is reached. The arms I1 and I9 must be insulated from each other and I therefore place between them a piece of insulating material 22 having the same shape as these arms and provided at one end or side with an extension 23 that lies against the inside of the arm I6 and thus prevents this arm from coming in contact with the adjacent edge of the arm I9 of the other contact piece.

The cover of the receptacle is prevented from being lifted off by a suitable shoulder on the upper end of the post. In the arrangement shown, the post is abruptly enlarged in diameter when it reaches the cover, as indicated at 24, thus providing a fairly wide annular shoulder against which the arm Il may be pressed. Upward or outward pressure on the arm II, to hold it against the overhang of the enlarged part 24 of the post, is produced by a coiled compression spring 25 much larger in diameter than the post, arranged within the interior of the stem and engaged at its upper end with the arm I9. The spring 25 rests at its lower end upon a follower 26 having a tubular part 21 extending up into the spring to hold the latter centered. The follower is a sleeve having a bore whose diameter is greater than the diameter of the post, as well as the diameter of the hub or sleeve 4. The bore in the follower is enlarged or flared atitslowerend to provide an internal frustoconical seat 28 complementary to the frusto-conical surface on the member 9 which forms part of the contact finger 6. The spring is placed under a slight initial compression when the parts are assembled, so that it forces the follower down against the frusto-conical member 9 and forces the arms I1 and III, with the layer of insulation interposed between them, up against the inner side of the cover and against the annular shoulder around the lower end of the enlarged part 24 of the post. It will thus be seen that the contact piece I5 is in electrically-conductive relation to the post 24 which is in turn electrically connected to the contact finger 5. Similarly, the contact piece I8, through its arm I9, has electrically-conductive connection with the spring 25 which contacts with the follower 26, while the follower in turn contacts with the frusto-conical member 9 on the contact finger 6. Therefore, the contact piece I5 and the contact finger 5 are electrically connected as are the contact piece I8 and the contact finger Ii.

That portion 30 of the bore in the cover through which the post passes that constitutes the lower section of the bore is shorter than the enlarged part 24 of the post. Above the section 30 the bore is enlarged, as indicated at 3I, to receive a head, 32 on the upper end of the post. With this arrangement, the cover does not bear against the under face of the head 32 and the only faces on the relatively rotatable parts in the vicinity of the cover that are held against each other under pressure are that portion of the upper face of the arm II that underlies the enlarged part 24 on the post, and that part of the annular overhanging under face of the section 24 of the post that contacts with the arm I1. Therefore, since the parts are so proportioned that the cover does not normally rest on the up per edge of the cup-shaped portion of the receptacle, the only resistance to rotation of the cover is the friction between the arm I1 and the part 24 of the post, and the friction between the follower 28 and the frusto-conical member 9; since the spring forces the follower down against the member 9. The surfaces at which frictional resistance to rotation of the cover occurs are close to the axis of the post so that a pair of contact fingers extending inwardly through the openings I2 and I3 in the cover have the advantage of being disposed comparatively far away from the axis of the post and therefore may exert a leverage that will cause the cover to turn when only a small turning force is applied. Therefore, in the use of the device, when it is attempted to twist a cord plugged into the receptacle, the torsion will be great enough to cause the cover with its contact pieces to turn before the cord can be objectionably stressed.

It should be noted that, while the cover normally stands free so as to permit easy turning thereof, whenever sufficient pressure is applied, the cover with the parts carried thereby can move down until the cover rests on the cupshaped member, thereby protecting the parts inside of the receptacle by relieving them of the load which would otherwise come upon the same.

I make use of the capacity of the cover to turn easily to facilitate the making of a connection in the dark or when the receptacle is so located that the positions which the openings therein occupy cannot readily be discerned. To this end I so shape the outer face of the cover that, whenever the contact fingers on a plug or other device are pressed against the cover in the manner of inserting the fingers to establish a connection, the cover will be turned until the openings therein are brought into registration with the fingers. By this means the fingers and the openings will not only automatically find each other, but it becomes unnecessary to twist the plug or other device inorder to make the connection, as the necessary twisting or turning is done by the cover. The proper cam faces to cause the cover to turn are provided by dishing the upper or outer face of the cover, as indicated at 33. Extending diametrically across the concavity thus formed is a ridge 34 between and parallel with the openings l2 and I3; this ridge sloping downwardly from the top in opposite directions to the inner margins of these openings. The slopes in the concavity proper also lead down to the finger-receiving openings. Consequently the outer face of the cover may be said to'have two concavities which are semi-circular at the top and slope gradually down to themargins'of the contact finger-receiving openings. The resuit is that, whenever a finger, such as indicated at in Fig. 1, is pressed into one of these concavities, there will be a wedge or cam action tending to turn the covenwhile moving the contact finger laterally, until the finger registers with the corresponding opening in the cover andslips into the same.

In Fig. 8, I have shown a somewhat diiferent arrangement in which there is a cup-shaped receptacle 40 of insulatingmaterial and a cover 4| also of insulating material. The contact finger 42, corresponding to the finger 5 in the other form, is attached by riveting over the end of the post 43, whereas the contact finger 44 is fastened to the receptacle by a rivet 45 passing through a part of the finger and the bottom wall of the cup. The cover has a tubular stem 46 surrounding the post. The contact fingers 41 and 48, lying beside the post, have at their inner or lower ends laterally bent portions 49 and 50, respectively. that surround a reduced neck portion 5i on the lower end of the stem; there being a layer 52 of insulation between the parts 49 and 50. The part 49 is below the part and rests upon a leaf spring 53 which overlies and bears on the inner end of the rivet 45. This spring presses up on the arm or flange 49 of the contact piece 41 which in turn presses the insulation 52 and the element 50 of the other contact piece up against the lower end of the stem and tends to push the stem up. The upward movement of the stem and therefore of the cover, is limited by a head 54 on the upper end of the post. Surrounding this head is an annulus 55 having a finger 56 extending laterally through a slot 51 in the stem. The free end of the finger 56 extends down far enough to overlap the upper end of the contact piece 48 which lies just outside of the same. It will thus be seen that the contact piece 48 is electrically connected to the finger 42, whereas the contact piece 41 is electrically connected to the finger 44.

It will thus be seen that I have produced a simple and novel swivel connecter of the quickly detachable type which offersvery little resistance to relative turning movements of the two members thereof, thereby making unnecessary the use of ball bearings to secure comparative freedom of relative turning movements, It will also be seen that the connecter functions not only as an ordinary swivel connecting device but also as an automatic adjusting device which brings the openings therein into registration with contact fingers when the fingers are simply pushed against the connecter while held parallel to the axis of rotation of the rotatable member.

While I have illustrated and described with particularity only a single preferred form of my invention, with a single modification, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim:

1. In a device, of the character described, a receptacle open at one end, a cover over said open end, a post fixed in the receptacle and passing freely through the center of the cover, a shoulder on the outer end of the post to engage the cover when it has been lifted a short distance from the receptacle and hold it against further outward movement while permitting it to rotate, said cover having openings through the same for the entry of contact fingers on a cable or other device, contact pieces in the receptacle in position to engage with said contact fingers when the latter are entered through the openings in the cover, and a spring within the receptacle tending constantly to hold said cover against said shoulder and out of contact with the receptacle.

2. In combination, a receptacle open at one end,

a post fixed in said receptacle and rising toward said end, a cover of insulating material for the receptacle rotatable on said post, a shoulder on the post to limit the outward movement of the cover to a position in which the cover is separated a short distance from the receptacle, a tubular stem of insulating material fixed to the cover and projecting inwardly therefrom around the post, contact pieces mounted on and movable with the stem, said cover having openings therein in registration with said contact pieces to permit contact fingers to be entered in said openings and be engaged with said contact pieces, and a spring acting on said stem and tending constantly to push it outwardly and hold the cover against said shoulder.

3. In combination, a receptacle open at one end, a post fixed in said receptacle and rising toward said end, a cover of insulating material for the receptacle rotatable on said post, a shoulder on the post to limit the outward movement of the cover to a position in which the cover is separated a short distance from the receptacle, a tubular stem of insulating material fixed to the cover and projecting inwardly therefrom around the post, contact pieces mounted on and movable with the stem, said cover having openings therein in registration with said contact pieces to permit contact fingers to be entered in said openings and be engaged with said contact pieces, a spring acting on said stem and tending constantly to push it outwardly and hold the cover against said shoulder, and means for connecting one of said contact pieces by way of the post to one side of a circuit and for connecting the other contact piece by way of the spring to the other side of such circuit.

4. In a device of the character described, a receptacle open at the top, a metal post rising from the bottom of the receptacle, a cover of in sulating material for the receptacle rotatable on and slidable lengthwise of the post, a shoulder on the-post for arresting the outward movement of the cover when the cover stands a short distance above the receptacle, a stationary frusto-conical member in the bottom of the receptacle aroundand spaced apart from said post, a tubular stem on the cover around the post, a compression spring surrounding the post within the stem, a follower below the spring fitted slidably in the stem, said follower having in the lower end an internal frusto-conical seat fitting around said frusto-conical member, contact pieces beside the said stem, the contact pieces having elements exon the post for rotation about the same. said structure including a cover for the receptacle and contact pieces underneath and carried by the cover, said post having a shoulder engaging with said structure over only a small area near the axis of rotation when the cover is raised out of contact with the receptacle, and spring means between said structure and the bottom of the receptacle exerting a downward thrust on the receptacle and holding the said structure up against said shoulder on the post, the bearing surfaces between said spring means and the bottom of the receptacle being of small area and near the axis of rotation of the cover.

6. In a device of the character described, a cup-shaped receptacle having terminals, 9. cover for said receptacle, contact pieces mounted on the cover within the receptacle, said cover having openings to receive contact fingers adapted to engage with said contact pieces, and means, including bearing surfaces of small area near the central axis of the receptacle, yieldingly to hold said cover rotatably in a position out of engagement with the receptacle and maintain electrically-conductive connections between said contact pieces and said terminals in all positions of the cover.

ALBERT E. CALDWELL. 

